The Efficiency of Vermiculite as Natural Sorbent for Heavy Metals. Application to a Contaminated Soil

Abstract

Vermiculite is a natural clay that has many applications as acoustic and thermal insulator, additive in concrete and plaster, fertilizer carrier and adsorbent. Moreover, clay minerals have been studied as adsorbent materials to remove heavy metals from industrial and/or municipal waste waters. In this work we have investigated the possibility to apply vermiculite for the clean-up of extracts resulting from the application of soil washing to a metal-contaminated soil collected from a polluted site in Italy. The soil was initially characterized for its total metal content; we also studied the availability of the pollutants by leaching at pH 5.0 and by Tessier's sequential extraction procedure. We tested a possible clean-up strategy, in which metals were extracted with hydroxylammonium chloride and vermiculite was used as natural sorbent for the decontamination of the extracting solutions. The possibility of recovering the metals by elution with acid and of reusing the clay was also demonstrated.

Spatial distribution and potential sources of trace elements in PM10 monitored in urban and rural sites of Piedmont Region

“…cement plant) emission sources; the other one is in Saliceto (SA), a village on the border with Liguria region, with only residential influences and no specific emission sources. This site was chosen also in consideration of its proximity to a heavily polluted area caused by the presence of ACNA, a former chemical plant located in the village of Cengio, that polluted waters and soils of the valley until 1999; since 1998 the area of the plant is listed among national interest sites with a high environmental risk (Abollino et al, 2007;Act n. 426, 1998). As this area has undergone remediation, SA is now classified as rural background site by ARPA Piemonte.…”

Metal-binding particles alleviate lead and zinc toxicity during seed germination of metallophyte grass Astrebla lappacea

“…Several substrate ameliorants have been trialled to precipitate or increase metal sorption in soils and therefore decrease the metal concentration in soil solution including lime [12], organic matter [13], vermiculite [14] and zeolite [15]. Hydrogels have been used to ameliorate plant growth in arid conditions [16][17][18][19][20] and saline or metal-contaminated soils [21][22][23] by providing a temporary source of water during germination and seedling establishment and diluting soil ion concentrations to tolerable levels [24].…”

Mercury, copper and zinc contamination in soils and fluvial sediments from an abandoned gold mining area in southern Minas Gerais State, Brazil

“…The biogeochemical behavior of heavy metals in the soil and fluvial sediments is related to physical, chemical and mineralogical properties of those compartments, such as pH, organic matter content, oxidation potential, electric conductivity, clay minerals, Fe and Al oxi-hydroxides and texture (Yin et al 1996;Hylander et al 2000;Abollino et al 2007). Distinct sources of pollution associated with specific chemical forms can also affect those processes (Katz and Salem 1993;Peakall and Burger 2003;Peijnenburg and Jager 2003).…”